Method of making propeller blades



July l0, 1934. F. E. wx-:lcK

l METHOD OF MAKING PROPELLER BLADES Fi1ed.April 8. 1925 3 Sheets-Sheet 1 July l0, 1934.

F. E. wElcK 1,965,622

METHOD 0F MAKING PROPELLER BLADES Filed.April 8, 1,925

3 Sheets-Sheet 2 Q O Q alito: eq

July 1o, 1934. F E WECK 1,965,622

METHOD OF MAKING PROPELLER BLADES Fi1ed.Apri1 8, 1925 5 Sheets-sheet :s

gwuemot FM-'Hack abbot mq Patented July 10, 1934 METHOD MAKING PROPELLEB BLADES Fred ErnestWeick, Washington, D. C., assignor to the Government of the United States Application April 8, 1925, Serial No. 21,737

3 Claims.

(Cl. Ztl-156.8)

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. '157) This invention relates to a method of making metal airplane propellers and more particularly to a method and machine for makingthe same in a single operation.

One of the objects of the present invention is to provide a means for manufacturing metal airplane propellers at a cost.

A further object is to provide a simple and practical method of finishingthe convex face of metal propeller blades in a single operation.

A further object is to provide for the manufacture of an airplane propeller constructed in relatively few parts which may be easily and quickly assembled.

L5 Other objects will be in part obvious and in part hereinafter pointed out in connection with the accompanying sheets of drawings illustrating more or less diagrammatically the machinery for making the same as well as the nished article.

In these drawings wherein similar parts are denoted by corresponding reference characters.

Figure 1 is a plan view of a blank of metal in position for milling.

Figure 2 is a side view of the same illustrating the manner in which the blade is supported on an incline and showing the stages of travel ofV blade secured to milling machine table as it is passed under a revolving formed milling cutter.

Figure 3 is a detail side view of a blade after the cut has been made.

Figure 4 is a plan view showing the convex face and outline formed by the single cut.

Figure 5 is a cross section on line 5-5 of Fig. .4. Figure 6 is a cross section on line 6-6 of Fig. 4. Figure 'I is a view of the blade after the hub end has been prepared to t the hub.

Figure 8 `is a rear view of a completed propeller (partly broken away) secured to the hub.

Figure 9 is a section on the line 9-9 of Fig. 8. Figure 10 is a section on the line 10-10 of Fig. 9.

Figure 11 is a view looking down at the tip of blade after being bent to conform to the proper air screw pitch. As is well known o subject the convex or rounded face of a propeller blade and the tapered outline in plan is such that the blade gradually tapers toward the tip and as hereinafter described this blade is machined by a single operation of a suitably shaped milling cutter extending entirely across the full width of the blade. In carrying out this operation, the blade may be machined flat on the inclined under-side and then twisted to the correct blade angles for each radius or it may be rotated while to those famuiar with this' passing under the revolving milling tool or the tool may be rocked as it passes over the blade.

These steps of operation being thoroughly familiar to those familiar with the subject, a further detailed statement of the specific means for carrying them out is believed to be unnecessary.

It is sufiicient to state that when the bladeis machined ilat the metal blank l from which it is t0 be cut is blocked or otherwise set upon the mill-f ying machine table with the tip end higher than the hub end to a predetermined height.

Because of the inclined lower surface and the aerofoil cross section the single horizontal cut of the formed milling tool extending the full width of the blade causes the blade to taper towards 70 the tip in plan view and have a gradual uniform taper in side View as shown more clearly in Figures 3'and 4.

After the cutting operation the blade may be bent at the proper radius points thereby to conform'to the proper pitch for the particular air screw. As herein illustrated the blade has the aerofoil or cross section and plan -form worked out in such a manner that the center of gravity of all of the sections lie substantially on a radial so line through the propeller axis.

The finished blade[2 as shown in Figure 8 may be secured to the hub in any desired manner but preferably by bolting it into a slot 3 Aas shown in Figure 10. This slot is provided with teeth in grooves adapted to fit into corresponding parts of the blade stub thereby to better take the stresses due to centrifugal force.

VFrom the above it will be seen that the present invention'contemplates a simple and practical metalpropeller blade and the method of making the same in a single cutting operation.

The invention described herein maybe manufacturedl and used by or for the Government of the United States of America for governmental purposes, without the payment of any royalties thereon.

What I claim is:-

1. A'process of manufacture of a screw-propeller blade from a solid block or blank of metal l00 of approximately the shape of the blade,'con Y sisting in machining one side of the blank flat, securing the blank with the machined surface downward on the bed of a milling machine with the end designed to form the tip of the blade higher than the other end, shaping Vthe upper surface of blade by a single operation of a milling cutter traveling parallel to the bed of the machine and by which different 'parts of the blade are shaped.

fing the blank, with the machined surface downward on the bed of a planing or shaping machine with the end designed to form the tip of the blade .higher than the other end, shaping the upper surface of the blade by a planing or shaping tool parallel to the bed of the machine and teling r/ lowered and rocked'automatically or by hand. according to the. contour required for the said face.

3. A modification of process claimed in .claim l, wherein the blanll twisted throughout the whole or a portion of its length prior to the cutting operation to take advantage of the varying camber of the cutter, and wherein the correct twist for pitch is imparted in a subsequent operation.

. FRED ERNEST WiglICK. 

